diff --git a/HISTORY.md b/HISTORY.md
index 520f4d8..97c9df8 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,6 +1,7 @@
 unreleased
 ==================
 
+  * refactor: replace setHeaders function with optimized inline header setting
   * remove unnecessary devDependency `safe-buffer`
   * remove `unpipe` package and use native `unpipe()` method
   * remove unnecessary devDependency `readable-stream`
diff --git a/index.js b/index.js
index f887765..f015e88 100644
--- a/index.js
+++ b/index.js
@@ -288,7 +288,9 @@ function send (req, res, status, headers, message) {
     res.removeHeader('Content-Range')
 
     // response headers
-    setHeaders(res, headers)
+    for (const [key, value] of Object.entries(headers ?? {})) {
+      res.setHeader(key, value)
+    }
 
     // security headers
     res.setHeader('Content-Security-Policy', "default-src 'none'")
@@ -318,23 +320,3 @@ function send (req, res, status, headers, message) {
   onFinished(req, write)
   req.resume()
 }
-
-/**
- * Set response headers from an object.
- *
- * @param {OutgoingMessage} res
- * @param {object} headers
- * @private
- */
-
-function setHeaders (res, headers) {
-  if (!headers) {
-    return
-  }
-
-  var keys = Object.keys(headers)
-  for (var i = 0; i < keys.length; i++) {
-    var key = keys[i]
-    res.setHeader(key, headers[key])
-  }
-}